Generate Perfect CSS Box Shadows

CSS supports unlimited comma-separated shadows. In practice, 2-4 layered shadows create the most realistic results. More than that increases rendering cost without noticeable visual improvement.

Adding the inset keyword creates an inner shadow — the shadow appears inside the element instead of outside. This is useful for pressed button states, input fields, and embossed text effects.

No. Box shadows are purely visual and do not affect the element's size or position in the document flow. They can, however, extend beyond the element's bounds and get clipped by overflow: hidden on parent elements.

Large blur radii and many layered shadows increase rendering cost. For most UIs, the impact is negligible. Avoid animating box-shadow values — animate opacity or transform instead, or use will-change: box-shadow for heavy shadows.